Retention Behavior of p-Alkylphenols in Reversed-Phase Liquid Chromatography Using Ethanol/Water Mixtures.

Abstract

The retention behavior of p-alkylphenols was studied in reversed-phase liquid chromatography using octadecylsilyl-silica gel and ethanol/water mobile phases. The results were compared with those in methanol/water systems. Linear correlations were observed between the logarithmic retention factor (ln k) and the carbon number of side chains in the solutes, irrespective of the type and volumetric fraction (φ) of the organic modifiers in the mobile phases. The straight lines mea-sured at different φ converged at almost one point. By analyzing the slope of the linear correlations, a functional contribution of a methylene group to k and a reduction of the hydrophobic surface area of the solutes and octadecylsilyl ligands due to the retention were estimated. It was also attempted to analyze the characteristics of the retention in reversed-phase liquid chromatography on the basis of solvophobic theory.